I am in on Detroit this year for NFC champs and the Chicago Bears for the most improved.
I think in the AFC the obvious pick is the Texans to be that new up an comer.... and as far as improvement I actually like the Chargers to improve this year.
Step back teams
NFC - Dallas - I just think they are ageing, with a core that hasnt gotten it done, and some significant players coming off of significant injuries
AFC - Dolphins - I think the losses on Defense, the injuries on Defense, the new Tua contract, the rules changes on forward motion at the snap, Hill getting older, Waddle seems to always be hurt.... expose them and they are only fringe contenders for the AFCE.